Add to your vocab sheet & Correct Inv. 4.4

Proteins or Polypeptides

Examples Nuts, meat (muscle), beans

Uses Muscle, hair, nails, skin, enzymes

Made from Amino Acid chains (polypeptides) that can be thousands of amino acids long There are only 20 amino acids in nature! -peptide

Enzymes

Large, complex proteins Help speed up the rate of chemical reaction (catalyst) –ase word ending (Lactase breaks down lactose) Activity varies with pH and temperature changes Can be denatured by extreme heat (shape is changed)

Eg. Think about an egg before and after it’s cooked. The egg proteins are denatured as it cooks.

Can be reused over and over again “Lock & Key” Model

Active Site: attracts and holds only molecules that have the right shape

Substrate: molecule that is changed by the enzyme – must have the right shape

Enzymes Video (click on it)

Example: Lactose Intolerance

Lactose is a sugar found in most milk products

Lactase is an enzyme that breaks down lactose

People who are missing lactase (can no longer produce it) can’t eat lactose unless they get artificial lactase.

Example: Lactose Intolerance

Investigation 4.4 Review

A monosaccharide turns Benedict’s solution from blue to orange after heating.

A polysaccharide turns iodine from amber/ yellow to dark blue/black without heating.

A disaccharide responds to neither Benedict’s nor iodine.

Table 4-1 Results of Tests with Known Carbohydrates

Tube Number

Carbohydrate Type

Benedicts Color After Heating

Iodine Color

1 Monosaccharide

Orange Amber/ Yellow

2 Disaccharide Blue Amber/ Yellow

3 Polysaccharide

Blue Blue/ Black

Table 4-2 Results of Tests with Unknown CarbohydratesCarbohydr

ateHypothes

is (Mono-, Di-, or Poly-)

Benedict’s Color After Heating

Iodine Color

Type of Carbohydrate

(after testing)

Honey Orange Amber/ Yellow

Mono – (fructose & glucose)

Oats Blue Blue/ Black

Poly- (starch)

Table Sugar

Blue Amber/ Yellow

Di- (sucrose)

Apple Juice Orange Amber/ Yellow

Mono- (fructose)

Powdered Sugar

Blue Amber/ Yellow

Di- (sucrose)

Maple Syrup

Yellow/ green

Amber/ Yellow

Mono- (fructose)some Di- (sucrose)

Investigation 4.5

You’ll be using the same testing methods as in lab 4.4 however you’ll do the lab in 3 Parts

1. Part A: Properties of Starch2. Part B: Properties of Salivary Amylase

(enzyme present in saliva – yes someone will be spitting, discreetly into a test tube!)

3. Part C: Properties of Starch Mixed with Salivary Amylase

At each Part you’ll test with both Benedict’s (and heat) and iodine (no heat) and record your data.

SAFETY!

No eating or drinking during the lab! Iodine and Benedict’s can stain and are

both toxic! Wear aprons and goggles if you

choose. If you are the generous saliva donor,

you will be the only one to handle, and wash your test tubes!

Set up Part C – 1st! (it needs to sit for 15 minutes minimum!)

READ the background info to help you with the DQ and Analysis Questions

Quiz on both labs (open notes/open lab) Thursday!